Growing suspension rates predict major negative life outcomes, including adult incarceration and unemployment. The first experiment tested whether teachers could be encouraged to adopt an empathic rather than punitive mindset about discipline—to value students’ perspectives and sustain positive relationships while encouraging better behavior. The second tested whether an empathic response to misbehavior would sustain students’ respect for teachers and motivation to behave well in class. These hypotheses were confirmed. Finally, a randomized field experiment tested a brief, online intervention to encourage teachers to adopt an empathic mindset about discipline. Evaluated at five middle schools in three districts, this intervention halved year-long student suspension rates and bolstered respect the most at-risk students, previously suspended students, perceived from teachers. Teachers’ mindsets about discipline directly affect the quality of teacher– student relationships and student suspensions and, moreover, can be changed through scalable intervention.